Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Vega: 01-16 (26), 01-15 (24), 01-13 (23), 01-14 (23), 01-12 (21) — by astronomy; check the weather when the night is within four days.

2028-12-18astronomy score per night — click a bar for that night2029-01-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-12-18 Mon	19	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:10	11.51	9%	61.4°
2028-12-19 Tue	17	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:05	11.51	15%	63.0°
2028-12-20 Wed	14	—	unknown	18:35–18:50 (good, 0.25 h)	87.1° 13:00	11.51	23%	65.9°
2028-12-21 Thu	12	—	unknown	18:35–18:40 (good, 0.08 h)	87.1° 12:55	11.51	32%	69.8°
2028-12-22 Fri	10	—	unknown	18:05–19:25 (marginal, 1.33 h)	87.1° 12:55	11.51	41%	74.4°
2028-12-23 Sat	8	—	unknown	18:40–19:20 (marginal, 0.67 h)	87.1° 12:50	11.5	50%	79.6°
2028-12-24 Sun	7	—	unknown	18:40–19:15 (marginal, 0.58 h)	87.1° 12:45	11.5	60%	85.1°
2028-12-25 Mon	7	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:40	11.5	69%	90.8°
2028-12-26 Tue	7	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:35	11.49	77%	96.6°
2028-12-27 Wed	7	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	85%	102.3°
2028-12-28 Thu	7	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	92%	107.6°
2028-12-29 Fri	6	—	unknown	05:55–06:10 (marginal, 0.25 h)	87.1° 12:25	11.47	96%	112.3°
2028-12-30 Sat	7	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.47	99%	115.9°
2028-12-31 Sun	7	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:15	11.46	100%	118.2°
2029-01-01 Mon	7	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	98%	118.8°
2029-01-02 Tue	8	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.44	94%	117.5°
2029-01-03 Wed	8	—	unknown	05:35–06:10 (marginal, 0.58 h)	87.1° 12:05	11.42	87%	114.4°
2029-01-04 Thu	9	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 12:00	11.41	78%	109.9°
2029-01-05 Fri	9	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 11:55	11.4	68%	104.2°
2029-01-06 Sat	10	—	unknown	05:25–06:45 (marginal, 1.33 h)	87.1° 11:50	11.38	57%	97.8°
2029-01-07 Sun	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:45	11.37	46%	91.1°
2029-01-08 Mon	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:40	11.35	35%	84.3°
2029-01-09 Tue	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:40	11.34	24%	77.9°
2029-01-10 Wed	17	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:35	11.32	16%	72.1°
2029-01-11 Thu	19	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:30	11.3	8%	67.3°
2029-01-12 Fri	21	—	unknown	05:30–06:10 (good, 0.67 h)	87.1° 11:25	11.28	4%	63.8°
2029-01-13 Sat	23	—	unknown	05:30–06:10 (good, 0.67 h)	87.1° 11:20	11.26	1%	61.7°
2029-01-14 Sun	23	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:20	11.24	0%	61.2°
2029-01-15 Mon	24	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:15	11.22	2%	62.3°
2029-01-16 Tue	26	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 11:10	11.2	5%	64.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-12-18&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.